Abstract:
PURPOSE: A decision feedback equalizing device of digital broadcasting is provided to use a TCM(Trellis-Coded Modulation) decoder where a TBD(Trace Back Depth) is 1 as a symbol detector, thereby exactly deciding a symbol without a decoding delay. CONSTITUTION: An FFF(Feed Forward Filter)(200) and an FBF(Feedback Filter)(240) remove an interference component from a signal. A TCM decoder(220) decides a symbol for the signal passing through the FFF(200) and the FBF(240), wherein a TBD of the TCM decoder(220) is 1. An error calculator(280) calculates an error signal. A training sequence storage(260) prestores an appointed training sequence among received data.
Abstract:
PURPOSE: A terrestrial digital broadcasting system by using a single frequency network(SFN) and a method thereof are provided to synchronize an input signal of a transmitter by inserting a transmission synchronization signal into a header of TS(Transport Stream) periodically and initialize a memory by a separate switching unit of a trellis encoder, thereby solving ambiguity of the trellis encoder. CONSTITUTION: A broadcasting station(400) multiplexes image signal compressed by MPEG-2, voice compressed by dolby AC-3 and additional data signal by a multiplexer and transmits the multiplexed signal to the first and second transmitters(430,470) by TS as a digital data stream. The first and second transmitters(430,470) process the transmitted TS and broadcast to the first broadcasting region(450) and the second broadcasting region(490), respectively with the same frequency A.
Abstract:
PURPOSE: A pre-equalizer, a VSB transmission system and method using the pre-equalizer are provided to obtain a correct bit precision for pre-equalization and stably transmit signals using the pre-equalizer. CONSTITUTION: A pre-equalizer includes the first and second memories(110,130), and an equalizer(120). The first memory stores the first transmission signal inputted from the outside. The second memory stores the second transmission signal that is obtained by modulating the first transmission signal, transmitting the modulated signal and then demodulating the signal. The equalizer calculates a bit precision on the basis of an error value that is a difference between the first and second transmission signals stored in the first and second memories, respectively, and carries out pre-equalization based on the bit precision.
Abstract:
PURPOSE: A blind decision feedback equalization device is provided to select an input of a feedback filter according to an SAG(Stop-And-Go) flag in order to reduce an error caused by quantization, thereby reducing error propagation and reducing a symbol error rate in a normal state. CONSTITUTION: A main filter(300) performs a blind decision feedback equalization process for a time index, and outputs a signal. An SAG flag determiner(340) determines an SAG flag according to SAG algorithm, based on a data symbol and the outputted signal. A blind decision feedback controller feeds back either the outputted signal or the data symbol according to the SAG flag to the mail filter(300) as a feedback signal. The mail filter(300) updates a tap coefficient according to the SAG flag, and performs the blind decision feedback equalization process based on the updated tap coefficient and the feedback signal.
Abstract:
PURPOSE: A blind decision feedback equalizing system and method are provided to control a blind equalization mode according to the output value of an equalizer to improve convergence speed of a filter and reduce residual mean square error in the normal state after convergence. CONSTITUTION: A main filter(200) perform blind decision feedback equalization through repeated filtering of input signals. A quantizer(220) quantizes the output signal of the main filter. An error signal calculator(230) compares the output signals of the quantizer and main filter to calculate an error signal. An equalization mode decision unit(240) calculates an estimated mean square error using the error signal, and than decides an equalization mode using the estimated mean square error. A blind mode decision unit(250) decides a corresponding mode when the equalization mode is the blind mode. An error signal calculator(260) calculates an error signal for the decided equalization mode. A tap modulus updating unit updates a tap modulus applied to the main filter using the error signal and the output signal of the quantizer.
Abstract:
본 발명은 무선 디지틀 신호 반송파 주파수를 스팩트럼 측정 방법중 FFT(Fast Fourier Transform)를 이용하는 방법에 있어서, 상기 FFT처리후 통계적으로 안정된 FFT처리결과를 얻기 위해 평균을 취하고, 상기 평균된 FFT에서 최대값을 추출하는 제1단계, 상기 추출된 주변의 값을 이용하여, 커브피팅(Curve Fitting)을 행하는 제2단계와, 상기 제2단계에서 커브피팅의 최대값을 추출하는 제3단계 및 상기 최대값 앞, 뒤의 3개의 값을 이용한 선형보간법에서 구한 최고값을 반송파의 주파수로 추정하는 제4단계를 구비하고 있는 것을 특징으로 하는 반송파 주파수 추정 방법을 제공한다.
Abstract:
A device for transmitting a digital broadcast signal and a receiving for receiving a digital broadcast signal using ZCD(Zero Correlation Duration) and LCD(Low Correlation Duration) spreading codes is provided to improve the performance of a system by deriving correlation characteristics through a matching filter of a receiving end. Digital broadcast data is modulated according to ATSC(Advanced Television Systems Committee) standards(S100). ZCD code and LCD code having characteristics of a continuous zero correlation duration are inserted to the modulated digital broadcast signal(S200). The generated broadcast signal is transmitted(S300). A signal watermarked with ZCD code and LCD code maintaining continuous zero correlation duration characteristics is received from multiple transmitters using the same frequency(S400). Correlation characteristics are derived from the received signal by using a matching filter and a transmitter is recognized according to the result of the correlation characteristics driving(S500). A broadcast signal received from the recognized transmitter is processed(S600).
Abstract:
본 발명은 차세대 텔레비전 시스템 위원회(Advanced Television System Committee, ATSC)의 디지털 텔레비전(Digital Television, DTV) 표준(A/53)에 관련된 잔류 측대파(Vestigial Side Band, VSB) DTV 송수신 장치 및 그 방법에 관한 것으로서, 보다 상세하게는, 일반 데이터의 1/4 전송률을 갖는 강인 데이터 생성을 통한 이중 스트림 구조의 DTV 송수신 장치 및 그 방법에 관한 것이다. 본 발명은 DTV 송신장치로서, 일반 데이터와 강인 데이터를 포함하는 디지털 영상 데이터 스트림을 입력받는 입력 수단; 상기 디지털 영상 데이터 스트림에 대하여 첫번째 심볼(R1)과 두번째 심볼(R2)의 2심볼당 1 비트가 전송되도록 1/4 레이트 코딩을 하는 인코딩 수단; 및 상기 인코딩수단의 출력 신호를 변조하여 전송하는 송신 수단을 포함한다. 본 발명은 강인 데이터에 대해 추가적인 FEC를 수행하여 2 심볼에 1 비트의 데이터가 전송되도록 하는 1/4 레이트 코딩된 강인 데이터를 송수신함으로써, 수신장치의 이퀄라이저 및 트렐리스 복호기의 복호 능력을 향상시켜 강인 데이터의 TOV를 만족시키는 SNR을 낮추는 효과를 제공한다. DTV, VSB, 강인 데이터, 일반 데이터
Abstract:
1. 청구범위에 기재된 발명이 속한 기술분야 동일채널 중계기 및 그 방법에 관한 것임. 2. 발명이 해결하려고 하는 기술적 과제 주송신기 또는 다른 중계기에서 전송된 신호로부터 수신 채널의 정보를 추출하고, 추출된 수신 채널 정보를 상기 수신된 신호에 역으로 반영함으로써 전송 채널상에서 발생된 채널 왜곡을 보상하고, 채널 왜곡된 신호를 수신 채널과 동일한 채널로 전송하는 동일 채널 중계기 및 그 방법을 제공함. 3. 발명의 해결방법의 요지 신호를 동일채널로 중계하기 위한 동일채널 중계기로서, 외부로부터 전송된 RF(Radio Frequency) 신호를 수신하기 위한 수신수단; 상기 수신된 RF 신호를 원하는 대역의 신호로 변환하기 위한 하향변환수단; 상기 하향 변환된 신호로부터 수신 채널의 역(inverse)을 추정하기 위한 채널추정수단; 상기 추정된 수신 채널의 역의 정보를 가지는 필터를 이용하여 채널 왜곡을 보상하기 위한 필터링수단; 채널 왜곡이 보상된 신호를 RF 신호로 변환하기 위한 상향변환수단; 및 상기 상향 변환된 RF 신호를 전송하기 위한 전송수단을 포함함. 4. 발명의 중요한 용도 신호를 동일 채널로 중계하는 모든 시스템에 이용됨. 동일 채널, 중계, 채널 왜곡, 채널 추정, 채널 왜곡 보상
Abstract:
A frequency domain equalization apparatus and a method thereof are provided to obtain an inverse of a changed channel, by changing a nonminimum phase channel into a minimum phase channel using a channel-matched filter and a noncausal filter. In a frequency domain equalization apparatus, a channel estimation unit(200) estimates a channel of a received signal inputted from the outside. A channel-matched filtering unit(210) changes the channel estimated in the channel estimation unit and channel characteristics of the received signal into channel characteristics for satisfying a condition required in noncausal filtering. A noncausal filtering unit(220) changes the channel characteristics changed through the channel-matched filtering unit from a nonminimum phase channel into a minimum phase channel. An inverse channel calculation unit(230) obtains an inverse of the channel changed through the noncausal filtering unit in a frequency domain. A frequency domain equalization unit(260) performs channel equalization in the frequency domain as to the channel changed through the noncausal filtering unit by using the inverse obtained in the inverse channel calculation unit as a frequency domain equalization coefficient.